Preheat oven to 350. In a heavy pot, dissolve the cornmeal in the cold water. Add the salt and bring to a boil over high heat, stirring constantly. The cornmeal will thicken as it cooks.
When it has thickened, turn heat to medium, cover, and cook for 25 minutes, stirring frequently. Add more water if it becomes too thick to stir. Halfway through cooking time, add oil.
Spoon mixture into a lightly oiled pie plate or loaf pan and bake, covered, for 30 minutes. Cool and slice.